Vehicle torques, particularly of motorcycles, have constantly increased in the past years. That is why the actuating forces of clutches are also more and more increasing. At the same time, the motorcycle manufacturers increasingly address female customers in order to extend their market share. This makes it necessary to enhance the comfort for the male or female driver with suitable measures by way of a small manual force for the clutch.
At the same time, the above-mentioned high transmittable clutch torques entail the safety problem that the rear wheel may start to hop under deceleration or overrun conditions if there is e.g. a downshifting to high revolution speed. In principle, this can be avoided when the clutch is opened on deceleration or overrun or is operated in the slip mode. Experienced drivers may take such a measure themselves by pulling the clutch lever in a finely regulated manner. However, to minimize the risk for all drivers, the use of an automatically usable mechanism is desirable, such mechanism opening the clutch on deceleration or overrun at least in part.
Clutch systems that are known on the market apply an additional force to the pressure plate on deceleration or overrun or to the piston of the clutch in an opposite direction relative to the spring force so as to open the clutch. This always creates an impact on the clutch lever due to the lifting of the pressure plate, which is considered by the driver as objectionable. Furthermore, these clutch systems operate with additional springs, whereby the manufacturing costs are increased.